A conventional vehicle lamp generally includes a reflecting seat for reflecting light to project the same forwardly out of the conventional vehicle lamp. The reflecting seat has a reflecting surface generally formed through a vacuum coating process. However, choice of the material of the body of the reflecting seat is limited due to the high temperature condition required by the vacuum coating process. In addition, the bonding ability of a coating layer on the inner side of the body of the reflecting seat also restricts the choice of the material of the body of the lamp cover. Moreover, since the vacuum coating process often causes the reflecting surface to be uneven, the optical precision of the conventional vehicle lamp is affected, thereby resulting in an undesired projected light shape, and thereby also affecting the reflectability of light which leads to great light loss.
Accordingly, a vehicle lamp lens has previously been designed specifically to improve the abovementioned drawbacks. Light that enters such lamp lens will exit through a light output surface of the lamp lens after undergoing total internal reflection (TIR). According to a theoretical calculation, reflectivity of such lamp lens may reach 100%. In comparison with the vehicle lamp having the abovementioned vacuum-coated reflecting seat, a vehicle lamp equipped with the previously designed lamp lens relatively has a reduced light loss and an improved optical precision.
Taiwanese Patent No. 1491833 discloses a vehicle illumination apparatus including a light source and a collimator lens. The collimator lens guides light emitted from the light source through TIR. However, the output light from such collimator lens may result in undesired residual light on the illumination plane, which causes occurrence of glare and hence negatively affects passerby and drivers. For example, light emitted from a low-beam lamp may generate residual light at a zone above the cut-off line.